The present invention relates to an image input device used in inputting an image into an image processing apparatus.
With the recent progress in image processing techniques, various image processing methods have hitherto been employed in the medical field, as well. For example, angiography is used as one method of diagnosis of the circulatory organs. This method consists of inserting a catheter into the heart or blood vessels, injecting a contrast medium into the blood vessels through the catheter, and imaging the flow of the resultant contrast medium by an X-ray imaging apparatus. The X-ray image obtained through the irradiation of X-rays is imaged by a TV camera, and the output image signal from the TV camera is converted to a digital signal by an analog-to-digital converter. The digital signal is input into a computer, whereby the image processing is carried out.
When a portion to be diagnosed, which is injected with such a contract medium, is imaged, the position thereof on the entire picture screen, the magnification thereof, etc., are widely varied, according to the imaging conditions. Furthermore, since portions to be diagnosed might include such portions as, e.g., the heart, which change in shape over time, it is likely that the object to undergo diagnosis will be displaced from the central portion of the picture screen; or, at worst, will be partially or wholly lost from the screen.
In the prior art, therefore, image inputting has been carried out while the position and configuration of the object on the picture screen are being anticipated and the imaging condition is being adjusted accordingly. However, if a person making the image were to sensuously evaluate the position, configuration, and amount of variation over time of the object, and change the imaging condition accordingly, such an operation would be very time-consuming. In other words, as the number of images obtained was increased, the amount of time required would become exorbitant. Particularly when image processing is carried out on an on-line basis, a serious problem arises, in that the quantity of X-rays to be irradiated onto a patient increases.